title: Computed tomography findings of human polyomavirus BK (BKV)-associated cystitis in allogeneic hematopoietic stem cell transplant recipients.
abstract: BACKGROUND
  Over 70% of the general population worldwide is positive for antibodies against polyomavirus hominis type 1 (BKV). Polyomavirus can be reactivated in immunocompromised patients and thereby induce urogenital tract infection, including cystitis.
  
  
  OBJECTIVE
  To describe the computed tomography (CT) findings of human polyomavirus-induced cystitis in adult patients after allogeneic hematopoietic stem cell transplantation (allogeneic HCT).
  
  
  METHODS
  The study population was a retrospective cohort of 11 consecutive adult patients (eight men, three women; age range 22-59 years, mean 42.9 years) who received allogeneic HCT between December 2003 and December 2007 and were tested positive for urinary BKV infection. All CT scans were evaluated with regard to bladder wall thickness, mucosal enhancement, distinct layering of thickened bladder wall, and presence of intravesical clots, perivesical stranding as well as attenuation values of intravesical urine. Clinical data concerning transplant and conditioning regimen variables and laboratory parameters were correlated with degree and extent of imaging findings.
  
  
  RESULTS
  All patients had clinical signs of cystitis with different degrees of thickening of the urinary bladder wall. Well-delineated urinary bladder layers were present in six patients. Thickening of the urinary bladder wall was continuous in nine of 11 patients. Increased attenuation of intravesical urine was found in seven patients with hemorrhagic cystitis. Four patients had intraluminal clots. Perivesical stranding was not a major CT finding, occurring in a mild fashion in three of 11 patients. The clinical classification of hemorrhagic cystitis did not correlate with the analyzed imaging parameters. Patient outcome was not influenced by this infectious complication.
  
  
  CONCLUSIONS
  CT findings in patients with polyomavirus BK cystitis consist of different degrees of bladder wall thickening usually with good delineation of all mural layers and increased mucosal enhancement. These findings are not specific for BKV cystitis, but awareness of this differential diagnosis should help in the early diagnosis and correct management of this infectious complication.
authors.affiliation: Department of Diagnostic Radiology, Eberhard-Karls University, Tubingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Schulze
authors.forename: R
authors.initials: R
authors.lastname: Beck
authors.forename: A
authors.initials: A
authors.lastname: Igney
authors.forename: M
authors.initials: M
authors.lastname: Vogel
authors.forename: O
authors.initials: O
authors.lastname: Maksimovic
authors.forename: C D
authors.initials: CD
authors.lastname: Claussen
authors.forename: C
authors.initials: C
authors.lastname: Faul
authors.forename: M
authors.initials: M
authors.lastname: Horger
mesh_terms: D000328:Adult; D001739:BK Virus; D015331:Cohort Studies; D003287:Contrast Media; D003556:Cystitis / Q000150:complications / Q000175:diagnosis* / Q000821:virology; D003937:Diagnosis, Differential; D005260:Female; D006400:Hematocrit; D018380:Hematopoietic Stem Cell Transplantation; D006417:Hematuria / Q000209:etiology; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010976:Platelet Count; D027601:Polyomavirus Infections / Q000150:complications / Q000175:diagnosis* / Q000821:virology; D011856:Radiographic Image Enhancement / Q000379:methods; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014412:Tumor Virus Infections / Q000150:complications / Q000175:diagnosis* / Q000821:virology; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000821:virology; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide